Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Example Input: Abstract: We examined changes in estrogen receptors (ERs) in endometrial stromal and epithelial cells in cynomolgus macaques during artificially induced menstruation and repair. We used Silastic implants filled with either estradiol (E2) or progesterone (P) to treat spayed animals for 14 days with E2 followed by 14 days of E2 plus P. We then withdrew the P (but not the E2) implants and removed uteri 0, 0.5, 1, 2, 3, 4, 5, 7, and 14 days later. Uterine tissues were assayed biochemically for ER content, fixed for histology and frozen for immunocytochemistry of ER with monoclonal antiestrophilins. On day 0, ER levels in endometrium were low [1330 +/- 201 (n = 9) fmol/mg DNA]. An increase in total receptor was evident by 3-4 days of P withdrawal 2762 +/- 190 (n = 6) fmol/mg DNA; P less than 0.001]. Total receptor concentrations increased linearly with time from 0.5-7 days of P withdrawal (r = 0.88). On day 0, staining for nuclear ER in the glandular epithelium and stroma of zones I, II, and III of the endometrium was negative. Beginning at 12-24 h and continuing through 4 days of P withdrawal, nuclear staining became detectable and increased in intensity only in endometrial stromal fibroblasts and myometrial smooth muscle cells. The glandular epithelium of the endometrium did not develop nuclear staining until 5-7 days of P withdrawal, coincident with a 10-fold increase in the mitotic index of the epithelium of the upper zones. Thus, the increase in endometrial ER levels that occurred during the first 5 days of an induced luteal-follicular transition took place almost exclusively in stromal fibroblasts.
Example Output: Animal

Example Input: Abstract: Thirty adult Wistar rats underwent an extradural clip compression injury of 50 g of force for 1 minute at T-1. After injury, the animals were randomly separated into three groups: the control group received a saline infusion for the 2-hour treatment period; the second group was given a blood transfusion over 2 hours titrated to maintain mean systemic arterial pressure (MSAP) at preinjury levels; and the third group received an intravenous bolus dose of naloxone (10 mg/kg), followed by a 2-hour infusion of intravenous naloxone (2 mg/kg/minute). The rats were observed postoperatively for 15 weeks, during which their clinical recovery was measured weekly by the inclined plane technique. At 15 weeks, the spinal cords were removed and prepared for histological assessment. The blood pressure before, during, and immediately after injury did not differ statistically among the three groups. During the initial 2 hours after injury, blood transfusion produced a significant increase in MSAP (P less than 0.02) and hematocrit (P less than 0.001), but naloxone infusion did not result in a significant change in MSAP. Performance on the inclined plane at 15 weeks was 35.6 +/- 6 degrees, 32.7 +/- 4 degrees, and 36.1 +/- 6 degrees for the control, transfusion, and naloxone groups, respectively, and no significant differences were found (P greater than 0.05). Histological examination confirmed a consistent injury of moderate severity in all three groups with no major differences among groups. Thus, this study demonstrates no significant clinical benefit either from a blood transfusion to maintain MSAP or from naloxone given by bolus and infusion after an extradural clip compression injury of the rat spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)
Example Output: Animal

Example Input: Abstract: Thermography of the lumbar area was performed on 169 patients under two years of age. Twenty-four percent (21/87) of afebrile patients and nine percent (6/66) of febrile patients without meningitis had increased lumbar heat (false-positive). Sixteen patients with a cerebrospinal fluid pleocytosis and/or pathogens present demonstrated increased heat in the lumbar area. Clinical evaluation at a level of greater than 2 (0-10) had a sensitivity of 100% and a specificity of 80%. Thermographic evaluation at a grade of 6 or higher (0-10) for the presence of midline heat had a sensitivity of 100% and a specificity of 92%. Thermography of the lumbar area may be a useful clinical adjunct to screen for meningitis.
Example Output:
Human