shukoor65/lab-rag-model huggingface dataset:
The myth of the aortic annulus: the anatomy of the subaortic outflow tract. Surgical repair of the small aortic root is limited in part by the very structure of the outflow tract from the left ventricle. The root is not constructed on the basis of a ringlike annulus supporting the leaflets of the aortic valve. The only truly circular structure within the outflow tract is the junction of the aortic wall with the underlying ventricular structures, themselves partly muscular and partly fibrous. This circular ventriculoarterial junction is crossed by the semilunar attachments of the leaflets of the aortic valve, producing an interlinking arrangement between the expanded aortic sinuses and three triangles of fibrous tissue placed beneath the apexes of the commissures between the valve leaflets. The triangles form extensions of the left ventricle that are related, in part, to the pericardial cavity surrounding the heart. The arrangements of the attachment of the leaflets in malformed valves with two (or only one) effective leaflets are highly abnormal, although these valves are usually produced on the template of three aortic sinuses. The valve with two leaflets rarely gives problems during childhood. In valves producing "critical stenosis", there is usually only one effective leaflet, a condition due to incomplete liberation of two of the anticipated three commissures. Detailed study shows that, in these malformed hearts, the attachment of the leaflets is much more annular than in normal valves, with inadequate formation of the fibrous triangles.
Treatment of acute systemic toxicity after the rapid intravenous injection of ropivacaine and bupivacaine in the conscious dog. Two groups of six beagle dogs received rapid intravenous (IV) injections of ropivacaine or bupivacaine on two occasions in a blinded random fashion. Initially, a dose sufficient to cause convulsions (CD) was given followed by twice the CD (2 x CD), which was administered 48 h later. The CD of bupivacaine (4.3 mg/kg) and ropivacaine (4.9 mg/kg) caused significant (P less than 0.05) increases in heart rate and mean arterial blood pressure. There was no difference between drug groups. Seizures were abolished by 10 mg/kg of intravenous thiamylal. Endotracheal intubation and controlled respiration with O2-enriched air with no other treatment resulted in rapid and complete recovery in all dogs. All dogs receiving 2 x CD of bupivacaine (8.6 mg/kg) or ropivacaine (9.8 mg/kg) were initially treated with thiamylal and mechanical ventilation. Two dogs in the bupivacaine group developed hypotension, respiratory arrest, ventricular tachycardia, and ventricular fibrillation, which were resistant to closed chest cardiac massage, treatment with epinephrine, bretylium, and atropine, and direct current cardioversion. The four remaining dogs in the infusion group were successfully resuscitated. All of the animals in the ropivacaine-treated group survived the administration of the 2 x CD dose. Mild hypotension developed in one dog and was treated with intravenous epinephrine (0.75 mg). This resulted in nodal tachycardia, which was abolished after treatment with bretylium. Another dog had two 1-s bursts of premature ventricular contractions requiring no treatment. The rapid treatment of convulsions and cardiovascular toxicity resulted in a decreased number of deaths in both groups when compared with dogs from a previously published study in which no therapy was instituted. Thus, early aggressive treatment of central nervous system and cardiovascular system toxicity is capable of reducing the incidence of mortality associated with the rapid intravenous administration of excessive doses of local anesthetics.
Pulsed dye laser lithotripsy of bile duct stones. Efficacy and safety of pulsed dye laser lithotripsy was tested in 25 consecutive patients in whom bile duct stones could not be extracted after endoscopic sphincterotomy. The patients had one to six (mean, 1.8) bile duct stones (diameter, 10-35 mm; mean, 18 mm) located in the common bile duct (18 cases), the intrahepatic bile ducts (6 cases), or in a long cystic duct stump (1 case). Different approaches were tested depending on the presence of a T tube and on the localization of the bile duct stones. When a T tube was present (7 cases), the lithotripsy was performed under direct vision using a choledochoscope inserted through the T-tube tract. In 18 patients without a T tube in place, the lithotripsy was performed under fluoroscopy using a retrograde approach in case of common bile duct stones (14 cases) or under choledochoscopy using a percutaneous transhepatic approach in case of intrahepatic bile duct stones (4 cases). Fragmentation of all the bile duct stones and a complete bile duct clearance were obtained in all 11 cases with procedures performed under direct vision as compared with only 5 of 14 cases with procedures under fluoroscopic control. Moreover, 6 of the 9 failures using the latter approach were offered another session using a choledochoscope inserted through a percutaneous transhepatic tract and were also successfully treated. No complication related to the laser beam was noted. It is concluded that pulsed dye laser lithotripsy of bile duct stones (that are unable to be removed by standard endoscopic techniques) is safe and efficacious provided that it is performed under direct vision. Technical refinements are needed before this procedure can be reliably performed under fluoroscopy.
Utilization of bone scans in conjunction with prostate-specific antigen levels in the surveillance for recurrence of adenocarcinoma after radical prostatectomy. Follow-up evaluation of patients who have undergone radical prostatectomy routinely consists of serial bone scintigraphy and, more recently, prostate-specific antigen (PSA) levels. The utility of serial bone scans in combination with PSA levels is retrospectively reviewed in 118 men treated by radical prostatectomy for clinical Stage A or B disease who, at the time of surgery, had no evidence of metastatic disease. Of the 118 patients, 75.4% had no abnormality on either test (mean follow-up 32.4 mo), 9.3% demonstrated a detectable or rising PSA level with negative bone scan (mean follow-up 35 mo), and 8.5% exhibited a detectable and or rising PSA level and positive bone scan (mean follow-up 30.7 mo). Follow-up bone scans were read as either positive or indeterminate with undetectable PSA levels in 6.8% of patients (mean follow-up 27.3 mo). Critical review of the equivocal studies suggests that postoperative PSA levels more truly represent the clinical situation than bone scans. Following radical prostatectomy, routine bone scintigraphy provides little additional information when PSA levels are negative. If PSA becomes detectable or the patient develops symptoms, bone scintigraphy should then be performed.
Intrahypothalamic clonidine infusion prevents NaCl-sensitive hypertension. We have previously shown that dietary NaCl supplementation increases blood pressure and sympathetic nervous system activity in association with decreased norepinephrine release and increased alpha 2-adrenergic receptor number in the anterior hypothalamic area of salt-sensitive spontaneously hypertensive rats (SHR-S) but not in salt-resistant spontaneously hypertensive rats (SHR-R) or Wistar-Kyoto (WKY) rats. Further, acute microinjection of clonidine into the anterior hypothalamic area produced depressor responses that were augmented by high salt feeding in SHR-S but not in SHR-R or WKY rats. The current study tested the hypothesis that chronic infusion of clonidine into the anterior hypothalamic area prevents salt-sensitive hypertension in SHR-S. Beginning at age 7 weeks, immediately before initiation of 1% or 8% salt diets, clonidine (2 ng/min) or saline vehicle was infused into the anterior hypothalamic area or femoral vein of male SHR-S via osmotic minipump for 20 days. In SHR-S fed an 8% salt diet, chronic microinfusion of clonidine into the anterior hypothalamic area offset the hypertensive effect of the dietary salt supplementation and reduced the enhancing effects of dietary salt on left ventricular weight and plasma norepinephrine levels. In contrast, chronic microinfusion of clonidine into the anterior hypothalamic area did not significantly affect any of these measures in 1% salt-fed SHR-S. Intravenous infusion of clonidine at the rate used for the anterior hypothalamic area infusion did not alter any of these measures in 8% salt-fed SHR-S.
Integration of conservative surgery, radiotherapy, and chemotherapy for the treatment of early-stage, node-positive breast cancer: sequencing, timing, and outcome. The optimal means of combining breast-conserving surgery, radiation therapy, and chemotherapy for the treatment of patients with early-stage, node-positive breast cancer is not known. We reviewed the results in 295 patients treated at the Joint Center for Radiation Therapy and affiliated institutions from 1976 to 1985. All patients had positive axillary nodes on dissection, had no gross residual disease in the breast or axilla after surgery, and received breast irradiation (with or without nodal irradiation) and three or more cycles of a cyclophosphamide, methotrexate, and fluorouracil (CMF)-based or doxorubicin-containing regimen. Median follow-up in patients without any failure was 78 months. Breast failure rates were assessed in relation to the sequencing of radiotherapy and chemotherapy. The different sequences were not randomly assigned, and the characteristics of the sequence groups differed. The actuarial 5-year breast failure rate was 4% in 99 patients receiving radiotherapy before chemotherapy; 8% in 54 patients sequentially receiving some chemotherapy, then radiotherapy without concurrent chemotherapy, then further chemotherapy; and 6% in 116 patients receiving concurrent chemotherapy and radiotherapy. However, the failure rate was 41% in 26 patients who received all chemotherapy before radiotherapy. The crude incidences of local failure within 4 years of treatment in these groups were 3%, 2%, 4%, and 15%, respectively (P = .065 for all four groups not being the same). The actuarial 5-year local failure rate was 5% for 252 patients irradiated within 16 weeks after surgery compared with 35% for 34 patients irradiated more than 16 weeks after surgery. The 4-year crude incidences were 4% and 12% for the two groups, respectively (P = .06). These results suggest that delaying the initiation of radiotherapy may result in an increased likelihood of local failure. Formal randomized controlled trials will be needed to confirm these results and to improve the integration of these treatment modalities.
Disk drusen and angioid streaks in pseudoxanthoma elasticum. Visual field loss secondary to optic disk drusen became evident before the development of angioid streaks in a patient with pseudoxanthoma elasticum. The incidence of optic disk drusen in cases of pseudoxanthoma elasticum is 20 to 50 times greater than that in the healthy population. We postulate that the abnormal aggregation of macromolecules with a high affinity for calcium (resulting in abnormalities in elastin in cases of pseudoxanthoma elasticum) also develops at the cribriform plate, disrupting axonal flow and leading to disk drusen formation. Pseudoxanthoma elasticum is associated with marked cardiovascular and gastrointestinal morbidity. Moreover, macular hemorrhage and precipitation of angioid streaks have frequently been noted after trauma. Prompt diagnosis of pseudoxanthoma elasticum will allow necessary prophylaxis and must be considered in patients with optic disk drusen.
Prehospital hypertonic saline/dextran infusion for post-traumatic hypotension. The U.S.A. Multicenter Trial. The safety and efficacy of 7.5% sodium chloride in 6% dextran 70 (HSD) in posttraumatic hypotension was evaluated in Houston, Denver, and Milwaukee. Multicentered, blinded, prospective randomized studies were developed comparing 250 mL of HSD versus 250 mL of normal crystalloid solution administered before routine prehospital and emergency center resuscitation. During a 13-month period, 422 patients were enrolled, 211 of whom subsequently underwent operative procedures. Three hundred fifty-nine patients met criteria for efficacy analysis, 51% of whom were in the HSD group. Seventy-two per cent of all patients were victims of penetrating trauma. The mean injury severity score (19), Trauma Score plus Injury Severity Score (TRISS) probability of survival, revised trauma scores (5.9), age, ambulance times, preinfusion blood pressure, and etiology distribution were identical between groups. The total amount of fluid administered, white blood cell count, arterial blood gases, potassium, or bicarbonate also were identical between groups. The HSD group had an improved blood pressure (p = 0.024). Hematocrit, sodium chloride, and osmolality levels were significantly elevated in the Emergency Center. Although no difference in overall survival was demonstrated, the HSD group requiring surgery did have a better survival (p = 0.02), with some variance among centers. The HSD group had fewer complications that the standard treatment group (7 versus 24). A greater incidence of adult respiratory distress syndrome, renal failure, and coagulopathy occurred in the standard treatment group. No anaphylactoid nor Dextran-related coagulopathies occurred in the HSD group. Although this trial demonstrated trends supportive of HSD in hypotensive hemorrhagic shock patients requiring surgery, a larger sample size will be required to establish which subgroups of trauma patients might maximally benefit from the prehospital use of a small volume of hyperosmolar solution. This study demonstrates the safety of administering 250 mL 7.5% HDS to this group of patients.
High frequency of asymptomatic visual field defects in subjects with transient ischaemic attacks or minor strokes. The hypothesis that asymptomatic visual field defects can be found in patients with carotid transient ischaemic attacks (TIA) or minor strokes was tested. Twenty-two consecutive male patients with TIA and 18 patients with minor strokes from the carotid artery territory were examined by perimetry, cerebral computerised tomography and regional cerebral blood flow. Asymptomatic visual field defects were found in many TIA and minor stroke patients, 29% (5/17) and 57% (8/14), respectively (NS). Eighty-five per cent (11/13) of the scotomas were solely or predominantly located in the upper part of the visual field (P = 0.008 for absolute defects and P = 0.03 for relative defects). We conclude that both carotid territory TIA and minor stroke patients have a high frequency of asymptomatic visual field defects, predominantly located in the upper part of the visual field.
Gastroesophageal reflux disease. When antacids aren't enough. Gastroesophageal reflux disease is a very common condition that is usually manifested by heartburn or regurgitation. Reflux esophagitis, caused by mucosal exposure to the backflow of caustic gastric contents, is primarily a result of lower esophageal sphincter dysfunction. Diagnostic workup varies but commonly includes esophagoscopy, 24-hour esophageal pH monitoring, and radiography of the upper gastrointestinal tract. Treatment, which progresses from simple life-style changes and antacids to histamine2 receptor antagonists to omeprazole (Prilosec) or surgery, is tailored to individual needs and is generally successful.
Protruding atheromas in the thoracic aorta and systemic embolization. OBJECTIVE: To determine whether protruding atheromas in the thoracic aorta are a risk factor for systemic embolization. DESIGN: Case-control study. SETTING: A referral hospital. PATIENTS: A total of 122 patients with a history of stroke, transient ischemic attack, or peripheral emboli and an equal number of age- and sex-matched control patients. MEASUREMENTS: Evaluation using transesophageal echocardiography was done in case patients to detect protruding atheromas in the thoracic aorta and in control patients for cardiac indications other than emboli. MAIN RESULTS: Matched logistic regression showed that the presence of protruding atheromas was strongly related to the occurrence of embolic symptoms (odds ratio, 3.2; 95% Cl, 1.6 to 6.5; P less than 0.001). Furthermore, atheromas with mobile components were present only in case patients. When known risk factors for stroke (hypertension and diabetes) were added to the model, the presence of protruding atheromas remained an independent risk factor for embolic symptoms (odds ratio, 3.8). Hypertension was also independently associated with embolic symptoms (odds ratio, 2.7), but diabetes was not (odds ratio, 1.0). CONCLUSION: Protruding atheromas in the thoracic aorta can be detected by transesophageal echocardiography and should be considered as a cause of strokes, transient ischemic attacks, and peripheral emboli.
The antinociceptive effects of anterior pretectal stimulation in tests using thermal, mechanical and chemical noxious stimuli. Four behavioural tests have been used to study the antinociceptive effects of electrical stimulation of the anterior pretectal nucleus (APtN) in the rat. The antinociceptive effects of stimulating this nucleus, which lies dorsally in the posterior diencephalon, have recently been studied extensively but always using briefly applied heat stimuli. It is reported here that APtN stimulation effectively inhibited responses to briefly applied noxious pressure and longer-lasting noxious chemical (formalin) stimuli. Although the tail-flick reflex to noxious heat was very potently depressed by APtN stimulation, responses to noxious heat in the hot-plate test were not. Three doses of morphine were also studied with each test and it was concluded that 15 sec of 35 microA r.m.s. current into the APtN was as effective as 3-5 mg/kg morphine s.c. in the rat.
Constipation--some provocative thoughts [editorial] Constipation is a collective term with different definitions and manifestations. In the present communication, I hope to shed light on the pathogenesis, investigation, and treatment of these manifestations. The levator ani is the principal muscle of defecation; together with anorectal reflex actions, it conducts the act of defecation. Strainodynia is the term I give to excessive and exhaustive straining at defecation. Band strainodynia has normal stool character but elevated rectal neck pressure due to the presence of a fibrous band in the rectal neck. Diet strainodynia presents with lower stool weight and frequency than normal; the internal anal sphincter is fibrous. The stools in levator strainodynia have been repeatedly obstructed at defecation due to levator dysfunction. Idiopathic oligofecorrhea or infrequent defecation was studied in 146 patients. Three stages could be identified: the deep and the everted intersphincteric groove and the cone anus. Fecoflowmetry is introduced as a new method for investigating anorectal disorders. It measures the defecated volume per time unit, and provides quantitative as well as qualitative data concerning the act of defecation. Changes in the fecal flow parameters or curve configuration from normal point to a defecation disorder.
Thiamine deficiency in patients with congestive heart failure receiving long-term furosemide therapy: a pilot study. PURPOSE: To test the hypothesis that long-term furosemide therapy in patients with congestive heart failure (CHF) is associated with clinically significant thiamine deficiency via urinary loss. DESIGN: (1) Biochemical evaluation of thiamine status in hospitalized patients with CHF treated with long-term furosemide and in age-matched control patients. (2) Uncontrolled trial of the effect of intravenous thiamine on cardiac performance in a subset of six patients with CHF. SETTING: General medical ward of a teaching community hospital. PATIENTS: Twenty-three patients with chronic CHF receiving furosemide, and 16 age-matched control patients without heart failure and not taking diuretics. Daily furosemide doses were 80 to 240 mg, and duration of furosemide therapy was 3 to 14 months. Patients with identifiable causes of inadequate thiamine intake, absorption, or utilization or increased metabolic requirements were excluded. INTERVENTION: A 7-day course of intravenous thiamine, 100 mg twice daily, in six consenting patients with CHF. RESULTS: A high thiamine pyrophosphate effect (TPPE), indicating thiamine deficiency, was found in 21 of 23 furosemide-treated patients and in two of 16 controls (p less than 0.001). The mean (+/- SE) TPPE (normal: 0% to 15%) in furosemide-treated and control patients was 27.7 +/- 2.5% and 7.1 +/- 1.6%, respectively (p less than 0.001). Despite the high TPPE, the mean (+/- SE) urinary thiamine excretion in the furosemide-treated patients (n = 18) was inappropriately high (defined as greater than 130 micrograms/g creatinine), 410 +/- 95 micrograms/g creatinine, even in comparison with that in the controls (n = 14): 236 +/- 69 micrograms/g creatinine. In six patients treated with intravenous thiamine, the elevated TPPE decreased to normal, from a mean (+/- SE) of 27.0 +/- 3.8% to 4.5 +/- 1.3% (p less than 0.001), indicating normal thiamine utilization capacity. Left ventricular ejection fraction increased in four of five of these patients studied by echocardiography. CONCLUSIONS: These preliminary findings suggest that long-term furosemide therapy may be associated with clinically significant thiamine deficiency due to urinary loss and contribute to impaired cardiac performance in patients with CHF. This deficit may be prevented or corrected by appropriate thiamine supplements.
Enhanced malignant transformation induced by expression of a distinct protein domain of ribonucleotide reductase large subunit from herpes simplex virus type 2. The 1.3-kilobase (kb) Pst I DNA fragment C (Pst I-C) of herpes simplex virus type 2 (HSV-2) morphological transforming region III (mtrIII; map unit 0.562-0.570) encodes part of the N-terminal half of the large subunit of ribonucleotide reductase (RR1; amino acid residues 71-502) and induces the neoplastic transformation of immortalized cell lines. To assess directly the role of these RR1 protein sequences in cell transformation, the Pst I-C fragment was cloned in an expression vector (p91023) containing an adenovirus-simian virus 40 promoter-enhancer to generate recombinant plasmid p9-C. Expression of a protein domain (approximately 65 kDa) was observed in p9-C-transfected COS-7 and Rat2 cells but not in those transfected with plasmid pHC-14 (Pst I-C in a promoterless vector). In Rat2 cells, p9-C induced highly transformed foci at an elevated frequency compared with that of pHC-14. Introduction of translation termination (TAG) condons within the RR1 coding sequence and within all three reading frames inactivated RR1 protein expression from p9-C and reduced its transforming activity to the level seen with the standard pHC-14 construct. Wild-type p9-C specified a protein kinase capable of autophosphorylation. Computer-assisted analysis further revealed significant similarity between regions of mtrIII-specific RR1 and amino acid patterns conserved within the proinsulin precursor family and DNA transposition proteins. These results identify a distinct domain of the HSV-2 RR1 protein involved in the induction of enhanced malignant transformation. In addition, the data indicate that the mtrIII DNA itself can induce basal-level transformation in the absence of protein expression.