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Biomedical subjects

D Pathak

Publications and source records attributed to D Pathak.

At least 55 records · Page 3Linked to original sources
PubMed1989

Pathologic findings in mesangiopathic glomerulonephritis in Navajo Indians.

Immune complex-associated mesangiopathic glomerulonephritis was found in 64% of renal biopsies performed on Navajos over a 16-year period. It is characterized by mild mesangial expansion and predominant immunoglobulin (Ig) A and/or IgM deposits. Statistical analysis shows that glomerular deposits of IgG and C3, glomerular sclerosis, interstitial fibrosis, interstitial inflammation, and tubular atrophy are associated with renal insufficiency at the time of biopsy, and can be integrated into a pathologic index that has a high correlative value. Mesangiopathic glomerulonephritis is probably responsible for the high rates of non-diabetic end-stage renal disease seen in Navajo Indians.

Adolescent↗
PubMed1989

Effects of exercise training on common femoral artery blood flow in patients with intermittent claudication.

Exercise training is a commonly used rehabilitative therapy for patients with intermittent claudication (IC). However, it is not known whether blood flow through the major conduit vessel of the leg, the common femoral artery (CFA), increases with exercise training. We tested the hypothesis that peak CFA blood flow will increase with a supervised, lengthy, and individualized exercise training program. Subjects were 10 IC patients (eight men, two women) with a mean age of 61 +/- 7 (mean +/- SD) years who had either aortoiliac (n = 7) or femoropopliteal (n = 3) stenosis. Using noninvasive Doppler flowmetry, we measured CFA blood flow and ankle pressure at rest and after a maximum symptom-limited graded treadmill test before (T1) and after 3 (T2) and 5 (T3) months of exercise training. Variables were measured in the supine and upright postures at rest and during recovery. Total walking distance and claudication distance on the treadmill were determined for T1, T2, and T3. After training, CFA blood flow and ankle pressure were not significantly higher at rest or at 1 minute after exercise compared with pretraining despite significant increases in claudication and total walking distances. The rate of CFA blood flow recovery was slower at T3, suggesting the accrual of a larger metabolic debt during exercise due to more work performed. We conclude that changes in CFA blood flow are not responsible for measured changes in performance with exercise training in IC patients.

Blood Flow Velocity↗
PubMed1988

X-ray crystallographic structure of dienelactone hydrolase at 2.8 A.

The structure of dienelactone hydrolase, an enzyme of the beta-ketoadipate pathway, has been determined at 2.8 A resolution using multiple isomorphous replacement techniques. An unambiguous assignment of C alpha atoms to electron density has been accomplished and a preliminary identification of the active site made. Dienelactone hydrolase is an alpha/beta protein consisting of an eight-stranded beta-pleated sheet with seven parallel strands, surrounded by seven helices. Preliminary enzyme inactivation data and an examination of the atomic model have implicated cysteine 123, histidine 202 and aspartate 171 with the active site of the enzyme. It is believed that the enzymic mechanism of dienelactone hydrolase may be similar to that of the thiol and serine proteases.

Amino Acid Sequence↗
PubMed1988

Effects of a subanesthetic concentration of nitrous oxide on overt and covert assessments of memory and associative processes.

Drug effects on human memory are usually assessed by overt recall or recognition tests. Covert tests which do not explicitly assess memory but which indirectly elicit previously presented information may be more sensitive to low levels of learning than overt tests. Three covert tests and corresponding overt recall tests were given to 16 men and 16 women breathing 30% nitrous oxide in oxygen or 100% oxygen to see if the covert tests resisted the memory-impairing effects of nitrous oxide. Nitrous oxide impaired performance on the overt tests. Performance in two covert tests, Constrained Associations and Word Completion, showed resistance to memory impairment. In the least resistant covert test, Free Associations, nitrous oxide altered associative processes. Performance in an additional test involving recognition and preferences for nonsense words repeated with varying frequencies also showed some resistance to memory impairment. The results support the distinction between declarative and procedural memory. Constrained Associations, Word Completion, and Nonsense Words tests may be useful for assessing low levels of learning during drug states.

Adolescent↗
PubMed1988

Fears and beliefs in patients with the pelvic pain syndrome.

In order to explore attitudes and beliefs in patients with the pelvic pain syndrome, the authors matched gynaecological patients with this syndrome (N = 41) with other gynaecological patients. They administered the Illness Behavior Questionnaire and Illness Attitude Scales (that measure attitudes, fears and beliefs about illness) to both groups. In spite of thorough investigations, 18 patients (44%) with the pelvic pain syndrome believed that their physician had not diagnosed their illness correctly and feared that they had a serious disease. The findings appear to have implications for treatment.

Adolescent↗
PubMed1988

Trauma in the elderly.

One hundred geriatric patients who suffered injury severe enough to necessitate hospitalization were compared retrospectively to a random group of 100 younger patients. The elderly suffered different types of injury and died six times as often as their younger peers, even when controlled for injury severity. The PRE method was employed to examine outcome in both groups and was found to be strongly predictive of death in young patients. Age stratification aided significantly in predicting mortality in elderly patients. Regression analysis was employed to examine the data set to determine the relative importance of several variables in the prediction of ultimate mortality. By incorporating all the data from the entire data set, curves describing the contribution of age and shock to mortality corrected for all factors is possible. Increasing age after 65 increases mortality and this effect is dramatically increased by the presence of shock. This information may be useful in counselling the injured elderly and their families.

Adolescent↗
PubMed1988

Comparison of psychologic and cognitive functions after general or regional anesthesia.

The behavior of 105 patients randomly assigned to receive either general or regional anesthesia and who underwent one of three types of surgery (hysterectomy, prostatectomy, or joint replacement) was assessed before, immediately after, and 3 mo after surgery. Psychologic status was assessed by the Sickness Impact Profile, the SCL-90-R, and a Metamemory Questionnaire. Cognitive functioning was measured by a battery of ten psychomotor, memory, and skilled performance tasks. Physical health was scored by the ASA classification of physical status, a health index, postoperative complications ratings, and a self-rated measure of the patient's health. There were cognitive differences across surgery groups due to age and gender variability among the patients; however, the type of anesthesia produced no difference in behavior. Both the physical and mental health indices showed improvement from the preoperative to the postoperative periods. General anesthesia appears to pose no risk to mental function and recovery beyond that associated with regional anesthesia and surgery.

Adult↗
PubMed1988

Prolactin, cortisol, and antidepressant treatment.

In four depressed patients with abnormal dexamethasone suppression test results before treatment, plasma prolactin levels significantly increased after successful amitriptyline therapy. Such an increase did not take place in five depressed patients with normal dexamethasone suppression test findings.

Adult↗
PubMed1988

Cardiac output determinations in the newborn. Reproducibility of the pulsed Doppler velocity measurement.

Cardiac output (QAo) can be estimated noninvasively by pulsed Doppler (PD) ultrasonographic determination of mean ascending aortic blood flow velocity (VAo) combined with M-mode echocardiographic determination of ascending aortic cross sectional area (AAo). Cardiac output is calculated from the volumetric flow equation (QAo) = (VAo) X (AAo). Pulsed Doppler measurements are known to correlate well with Fick and thermodilution methods; however, inter- and intraoperator variability of the velocity component of the PD method has not been determined in newborns. We did three repeated PD measures of mean aortic flow velocity in ten term infants (using four trained operators) to determine inter- and intraoperator reproducibility. The coefficient of variation for intraoperator variability (random error) for a single measurement of VAo was 11.7%. If three repeated measures by a single operator were averaged, the random error was 7.0%. There was little interoperator variability found.

Aorta↗
PubMed1988

Studies of possible antiidiotypic control mechanisms in Graves' disease.

Serum from 55 patients with active Graves' disease and 55 patients who had received successful treatment (in whom the disease was inactive) were examined for the presence of possible antiidiotypic antibodies with an enzyme-linked immunosorbent assay (ELISA) for anti-F(ab')2. Murine IgG monoclonal antibodies (Mabs) against human thyroid-stimulating hormone (TSH) and human TSH receptors were also used as antigens in parallel ELISA assays. Patients with active and patients with inactive Graves' disease showed elevations of IgG anti-F(ab')2 antibodies when compared with normal controls. Similarly, both active and inactive Graves' disease sera showed higher levels of IgG anti-LE4, a mouse Mab to human TSH, than was seen with normal controls. However, F(ab')2 isolated from sera reacting with LE4 in the ELISA did not inhibit binding of the LE4 Mab with labeled TSH in a fluid phase competition assay. Patients with inactive Graves' disease showed higher ELISA reactivity with two different murine anti-TSH receptor Mabs than was recorded with either active Graves' or normal controls. A rough inverse correlation was noted between strongly positive ELISA reactions against these two Mabs with anti-TSH receptor specificity and the ability of immunoglobulins from inactive Graves' sera to stimulate increases in cyclic adenosine monophosphate (cAMP) in the normal rat thyroid cell line assay. Untreated Graves' sera showing high cAMP release only rarely showed elevated ELISA reactivity against Mabs with anti-TSH receptor activity.

Acute Disease↗
PubMed1988

Developing instruments for cross-cultural psychiatric research.

The growth of cross-cultural psychiatry is now occurring at a time when psychiatry in general is emphasizing diagnostic clarity and the use of quantifiable and reliable methods of collecting clinical and research data. It is now imperative that cross-cultural psychiatry also examine its methods for developing instruments for use in cross-cultural research. This paper outlines a method for developing instruments designed in one culture for use in a second, and particular attention is given to cross-cultural validity or equivalence. Five types of equivalence are enumerated and defined: content, semantic, technical, criterion, and conceptual equivalence. These concepts are illustrated by examples from the authors' experience in research on internal migrants in Peru.

Cross-Cultural Comparison↗
PubMed1987

Factors influencing discrepancies between premortem and postmortem diagnoses.

A study of 2067 autopsies collected from 32 university and community hospitals of various sizes located throughout the United States showed the rate of discrepancies between premortem and postmortem diagnoses to be influenced by the type and size of hospital, the age and sex of the patient, and the disease responsible for the patient's death. Of equivocal or no influence were the length of the terminal hospitalization, the degree of clinical involvement in the case of the person responsible for establishing the discrepancy level, and the autopsy rate, at least as it applies to community hospitals.

Adolescent↗
PubMed1987

Hypochondriacal concerns and somatic symptoms in patients with chronic airflow obstruction.

In order to explore hypochondriacal concerns in patients with Chronic Airflow Obstruction (CAO) the authors administered the Illness Attitude Scales and the somatization, anxiety, depression and anger-hostility scales of the Hopkins Symptom Checklist to 50 patients with CAO and to matched family practice patients. Somatic symptoms were significantly correlated with fears of disease and hypochondriacal concerns in family practice patients, but were unrelated in CAO. Patients with CAO, although more anxious, depressed and with more severe somatic symptoms than family practice patients, had fewer hypochondriacal concerns. In this respect patients with CAO were unlike any other group previously studied.

Adaptation, Psychological↗
PubMed1987

Effects of a subanesthetic concentration of nitrous oxide on establishment, elicitation, and semantic and phonemic generalization of classically conditioned skin conductance responses.

Classical conditioning of skin conductance responses was studied in 16 men and 16 women breathing 30% nitrous oxide or 100% oxygen to see how nitrous oxide affected establishment, elicitation, and generalization of conditioned responses (CRs). For CRs that had been established before gas inhalation, nitrous oxide blocked elicitation of "anticipatory" (long latency) but not "orienting" (short latency) CRs. Nitrous oxide appeared to prevent new CRs from being established during its inhalation, but learning evidently took place since anticipatory CRs could be elicited after nitrous oxide inhalation had ceased. Words were used as the conditioned stimuli and nitrous oxide altered generalization of CRs to other words related in meaning or sound, though generalization effects were limited. Nitrous oxide also seemed to reduce the efficacy of the unconditioned stimulus. The results were interpreted in terms of Rescorla's theory of classical conditioning.

Adult↗
PubMed1987

Fears, beliefs, and attitudes in DSM-III hypochondriasis.

In order to explore fears, beliefs, and attitudes of patients with DSM-III hypochondriasis, the authors administered the self-rated Illness Attitude Scales to 21 patients with hypochondriasis, matched family practice patients, nonpatient employees, and nonhypochondriacal psychiatric patients. Hypochondriacal patients reported more fears of and false beliefs about disease; they attended more to bodily sensations, had more fears about death, and distrusted physicians' judgments more, yet sought more medical care than other subjects. They did not take better precautions about their health. The self-report of overt attitudes suggests a characteristic syndrome, consistent with the DSM-III description of hypochondriasis. Two of the subscales of the Illness Attitude Scales yielded characteristic responses in hypochondriasis.

Adult↗
PubMed1987

Nonpsychotic patients referred to a consultation service.

In order to examine characteristics of nondangerous and nonpsychotic patients referred to a consultation service, the authors administered self-rating scales and questionnaires to fifty referred medical patients and nonreferred controls. Recalled abuse in childhood appeared a stronger predictor for referral than some other commonly researched ones such as parental death, divorce or separation in childhood or recent losses. Anxiety, hostility and depression were significantly higher in referred patients, whereas hypochondriacal attitudes did not differ between the two groups. The findings appear to have implications for treatment.

Adolescent↗