Biomedical subjects
Publications and source records attributed to R Park.
A patient with metastatic placental site trophoblastic tumor is presented. Her treatment included several aggressive chemotherapeutic regimens. In this patient, the clinical course and assays of beta-hCG (beta fragment of human chorionic gonadotropin) correlated with her response to these treatments.
The finding of osseous metaplasia within an ovarian papillary serous cystadenocarcinoma is very rare. A review of the medical literature reveals only two previously published cases where mature bone was found in an ovarian serous cystadenocarcinoma. This report presents an additional case of this unusual phenomenon whose clinical significance remains uncertain.
Flurbiprofen (Ocufen), an antiprostaglandin, has been introduced into cataract surgery. It is used to prevent intraoperative miosis by blocking inflammatory mediator formation. Ocufen has been noted to diminish the controlled miosis produced by using acetylcholine in the operative period. This study evaluated the pupillary response to acetylcholine after it had been exposed to Ocufen. This was done using a control versus a study eye in 16 rabbits dilated with phenylephrine hydrochloride and cyclopentolate hydrochloride. The pupil diameters were measured at baseline, then the rabbits' anterior chambers were irrigated with an acetylcholine solution. The resultant pupillary diameters were measured at one and five minutes. At five minutes post-irrigation there was a statistically significant greater constriction in the control group than in the Ocufen group. This implies that Ocufen dampens the iris musculature's response to acetylcholine.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The effect of intracerebroventricular (i.c.v.) infusion of various iso- and hypertonic saccharide solutions on water intake stimulated by intracarotid (i.c.) infusion of hypertonic NaCl was studied in sheep. Without an i.c.v. infusion, water intake during a 10-min period following an i.c. infusion of 4 M NaCl (1.4 ml/min over 20 min) was 1.5-2.0 litres. I.c.v. infusion of all saccharide solutions (made up in artificial cerebrospinal fluid (CSF) with no Na) tested, 0.27 or 0.7 M D-glucose, L-glucose, 2-deoxyglucose and sucrose, decreased (35-65%) water intake. In general, there was little or no difference in antidipsogenic effectiveness between the isotonic and the hypertonic solutions or between the different saccharides used. I.c.v. infusion of artificial CSF ([Na] = 150 mM) did not alter water intake. CSF [Na] was decreased by all of the saccharide infusions. CSF osmolality was increased by the hypertonic solutions, was decreased by the artificial CSF and was unchanged by the isotonic solutions infused. The observation that the antidipsogenic effectiveness of saccharides which readily cross the blood-brain barrier (BBB; D-glucose, 2-deoxyglucose) was similar to that of saccharides which do not readily cross the BBB (sucrose, L-glucose) contrasts with effects reported on sodium appetite and suggests that the Na sensors involved in the inhibition of hypertonic NaCl-stimulated water intake are located close to or on the surface of the brain ventricular system, i.e. are responsive to changes in CSF [Na].(ABSTRACT TRUNCATED AT 250 WORDS)
The cause of chest pain in diffuse oesophageal spasm and "nutcracker" oesophagus is not clear. Spasm of the oesophageal muscle itself is probably not the cause, because pain and spasm are frequently not coincident. It is suggested instead that oesophageal ischaemia may be the cause of the pain, since the rewarming rate of the oesophagus after a standardised cold challenge was significantly longer in 9 patients with these motility disorders than in 21 normal controls. As rewarming time in other sites correlates with blood flow, these results are consistent with the hypothesis that the oesophagus is ischaemic in these patients.
This report retrospectively analyzes 48 cases of primary vaginal cancer treated at Walter Reed Army Medical Center and the Naval Hospital, Bethesda, from 1962 through 1983. There was an unusually high number of uncommon histologic types. Nine patients had an adenocarcinoma, 5 had a sarcoma, 3 had a melanoma, 2 had an adenosquamous carcinoma, 1 had a lymphoma, and 1 had a carcinoid tumor. The remaining 27 patients had a squamous cell carcinoma. This represents a 43% prevalence of nonsquamous lesions. Nonsquamous cancer of the vagina occurred in patients at an earlier age than squamous cell carcinoma. Presenting symptoms, the location of the tumor within the vagina, and survival rates were similar for both groups. The clinical characteristics and treatment of the patients with nonsquamous tumors are discussed.
Hazardous chemical exposures may be a more important public health problem in chemical-using industries, such as the metalworking and transportation equipment industries, than in chemical manufacturing plants. Recent studies have identified excess mortality from cancer among groups of workers in model and patternmaking, plating and die-cast, foundry, machining, electronics operations and vehicle assembly plants. The chemical agents or levels of exposure associated with these findings have not previously been thought to pose a cancer risk. Therefore, estimates of the fraction of cancers associated with workplace exposure may understate the importance of exposure in this setting.
Epidemiologic studies have reported associations between gastrointestinal cancer mortality and exposure to cutting fluids and abrasives in metal machining and precision grinding operations. Two previous studies found excess stomach cancer among workers exposed to water-based cutting fluids in bearing plants. This study reports similar findings in a third and larger population. Cause of death and work histories were determined for 1,766 bearing plant workers who died between Jan 1, 1950 and June 30, 1982. Mortality odds ratios (SMOR) and proportional mortality ratios (PMR) revealed significant excesses of gastrointestinal malignancies. The proportional mortality excess for stomach cancer among white men was greatest among those with more than 10 years' exposure in the major grinding group (PMR = 13/3.8 = 3.39; P less than .001). The SMOR by logistic regression for stomach cancer among white men was 2.3 (P = .02) for 25 years' grinding experience. For cancer of the pancreas among white men, there were significant associations with both machining and grinding jobs in straight oil (SMOR = 9.9 and 3.2, respectively, for 25 years duration). These findings could not be explained by confounding due to the ethnic background of the decedents. This study confirms previous evidence that grinding operations using water-based cutting fluids increase the risk for stomach cancer and provides moderate evidence that exposures to straight oil-cutting fluids increase the risk for cancer of the pancreas. There were indications, meriting further investigation, that non-malignant liver disease is associated with cutting fluid exposures and that lung cancer is associated with oil smoke from operations such as forging or heat treating.
Explore the source record for details and available documents.
The U3 region of the long terminal repeat (LTR) of human T-cell leukemia virus type I (HTLV-I) contains sequences that respond to the trans-activating transcription (tat) factor encoded by the pX region of the provirus. Results presented here show that there are multiple tat-responsive sequences within the LTR and that a single 21-nucleotide sequence, which is repeated three times within the U3 region, is sufficient to determine the response to the trans-activator. This sequence is capable of conferring a tat-responsive phenotype upon the HTLV-I and simian virus 40 promoters, independent of orientation. Sequences required for efficient HTLV-I LTR-directed gene expression are also located 3' to the site of RNA initiation, within the R and U5 regions of the LTR.
Wide excision is the recommended primary therapy for retroperitoneal fibromatosis. Radiation therapy and a variety of medications have been used to treat patients with recurrent tumors, but the response to these agents has not been uniform. The patient presented was successfully treated with medroxyprogesterone acetate for recurrent retroperitoneal fibromatosis that was refractory to multiple operative resections and radiation therapy.
One hundred twelve patients with early (FIGO stage I and II) ovarian carcinoma had a second-look laparotomy performed after comprehensive surgical staging and randomization into clinical protocols. Of the 95 patients who were asymptomatic before second-look laparotomy, only 5% had positive findings. In contrast, 53% of the 17 patients with findings that suggested recurrence or bowel obstruction had disease at second-look laparotomy. Overall, only 13% of the entire group of 112 patients had recurrent disease at second-look laparotomy. Asymptomatic patients with early ovarian carcinoma who have undergone careful initial surgical staging followed by appropriate adjuvant therapy can be spared a routine second-look operation.
Mortality analyses were carried out for 278 male hourly workers who were employed for at least 10 years at a gray iron foundry and who died between January 1, 1970 and December 31, 1981. Statistically significant excess proportional mortality due to non-malignant respiratory disease (SPMR = 177), lung cancer (SPMR = 148), and leukemia (SPMR = 284) was found among the 221 white males. Among nonwhite males there was a significant excess in proportional mortality due to circulatory diseases (SPMR = 143). White males in the Finishing classification experienced a significant excess of proportional mortality due to nonmalignant respiratory disease (SPMR = 279) and lung cancer (SPMR = 179). White males in the Core Room classification experienced an excess of proportional mortality due to nonmalignant respiratory disease (SPMR = 321). Case-control studies demonstrated a significant association between nonmalignant respiratory disease and the Finishing classification after controlling for the effects of age, prior occupations in coal mining or foundries, and smoking. A positive but nonsignificant association between lung cancer and Finishing was also found after controlling for age, prior work history, and smoking in case control studies.
Catheter related sepsis (CRS) is the most serious complication of total parenteral nutrition. Frequently, however, low rates of CRS are associated with a high incidence of infection of the catheter tip, the clinical significance of which is unclear. The relationships between CRS, infection of the catheter tip and infection at the site of catheter insertion have been investigated in 283 catheters of 257 patients receiving total parenteral nutrition. CRS occurred in only ten patients (3.5 per cent) whereas organisms were isolated from 108 catheter tips (38.2 per cent). The most common organism isolated was Staphylococcus epidermidis (66.7 per cent). Eight catheter tips were colonized from a distant septic focus. Organisms were isolated from 90 catheter tips which were removed electively from patients who displayed no clinical evidence of sepsis. There was a poor correlation between infected catheter tips and infected catheter insertion sites. Asymptomatic infection of the catheter tip appears to be of little clinical relevance, resulting in no patient morbidity. Contamination of the catheter tip during or after removal seems to account for a significant proportion of these infections.
Explore the source record for details and available documents.