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Biomedical subjects

Y Shah

Publications and source records attributed to Y Shah.

32 records · Page 2Linked to original sources
PubMed1984

The femur length/head circumference relation in obstetric sonography.

The relationship of sonographic femur length to biparietal diameter (BPD) in utero may be useful in detecting short-limb dwarfism, hydrocephaly, microcephaly, and measurement errors. Because BPD can be adversely affected by head shape changes (e.g., dolichocephaly), falsely high or low values of femur length/BPD could result. Because head circumference is less affected by head shape changes than is BPD, it should be a better standard of head size against which to judge limb length. The authors report normal values for the relationship between femur length and head circumference, based on a cross-sectional analysis of 361 normal fetuses (15-42 weeks) using real-time ultrasound.

Cephalometry↗
PubMed1983

Descending inhibitory influences from periaqueductal gray, nucleus raphe magnus, and adjacent reticular formation. II. Effects on medullary dorsal horn nociceptive and nonnociceptive neurons.

1. This study examined the inhibitory effects elicited by brain stem stimulation on the somatosensory responses of trigeminal medullary dorsal horn (subnucleus caudalis of the spinal trigeminal nucleus) neurons. Single-unit extracellular recordings were obtained in chloralose-anesthetized cats. Neurons were classified as wide dynamic range (WDR), nociceptive specific (NS), or low-threshold mechanoreceptive (LTM). Conditioning stimuli were delivered to the periaqueductal gray (PAG), nucleus cuneiformis (CU), nucleus raphe magnus (NRM), nucleus reticularis gigantocellularis (NGC), and nucleus reticularis magnocellularis (NMC). 2. Over 97% of the neurons tested could be inhibited by stimulation in all regions except PAG. Stimulation in the PAG inhibited 91% of the neurons tested. There was no statistically significant difference in the incidence of inhibition of WDR and NS nociceptive (noci) neurons and the LTM nonnociceptive (nonnoci) neurons. 3. Mean stimulation intensities necessary to produce inhibition were determined for each neuron from each stimulation site. The current thresholds necessary to inhibit the responses of noci neurons were found to be significantly lower, on the average, than those of nonnoci neurons at stimulation sites in the PAG, CU, and NGC. 4. Inhibition of the responses of WDR neurons required a lower mean current than for NS neurons but was statistically significant only for PAG and NGC. Thresholds for inhibiting the responses of NS neurons were similar to those for inhibiting the responses of LTM neurons for all regions except CU, where LTM thresholds were markedly but not significantly higher. 5. Stimulation thresholds were found to be lowest in NMC, while in NGC, NRM, and CU they were all similar and slightly higher. Stimulation in the PAG required the highest currents to produce inhibition. 6. These results indicate that stimulation in NRM and PAG not only inhibits the responses of noci neurons but also those of nonnoci neurons. Furthermore, stimulation in reticular regions adjacent to NRM and PAG is frequently even more effective in inhibiting the responses of both noci and nonnoci neurons. In addition, WDR neurons are more effectively inhibited than NS or LTM neurons. These results are compared with those obtained using similar methods in cat lumbar dorsal horn.

Animals↗
PubMed1983

Simultaneous appearance of keratin modifications and gamma-glutamyltransferase activity as indicators of tumor progression in mouse skin papillomas.

gamma-Glutamyltransferase (GGT), an enzyme not found in normal adult epidermis, was detected in most skin papillomas larger than 13 mm in diameter and in all squamous carcinomas induced by 7,12-dimethylbenz[a]anthracene initiation and 12-O-tetradecanoylphorbol 13-acetate promotion in noninbred Sencar mice. Furthermore, these GGT-positive lesions were also characterized by a marked decrease or absence of high-molecular-weight components of epidermal keratin. Since these characteristics are common to both carcinomas and large papillomas but are practically undetectable in normal epidermis and small papillomas, GGT activity and lack of high-molecular-weight keratin components seem to be good indicators of tumor progression, i.e., from papilloma to squamous carcinoma.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

Advanced ultrasound evaluation of fetal hydrocephaly.

Advancing technology of ultrasound imaging has unraveled numerous problems in perinatology. The 1980's is the era of high-resolution real time ultrasonography, enabling the diagnosis of fetal hydrocephaly to be made in midtrimester pregnancy even prior to the age of fetal viability. The findings obtained by full evaluation of hydrocephalic fetuses with serial ultrasounds are helpful in appropriate counseling of parents by the birth defects team and in planning the best time and management of delivery in a perinatal center. Arrest of progression of severe hydrocephaly in the second half of pregnancy prior to fetal lung maturity has been accomplished by intrauterine implantation of ventriculoamniotic shunts. The potential risk of maternal soft tissue injury from delivery of an oversized head of a severely compromised fetus can be minimized by partial and slow decompression of fetal head under ultrasound guidance using a #20 spinal needle. The influence of the recent developments on better fetal diagnosis and survival of infants with neural tube defects in 1981 was compared to that obtained during the previous five years.

Female↗
PubMed1980

Combined intra- and extrauterine pregnancy. A diagnostic challenge.

A case of combined intrauterine and tubal pregnancy is reported and illustrates the difficulties of correctly diagnosing combined pregnancy. The patient had no signs or symptoms suggestive of a tubal pregnancy at the time of termination of the intrauterine pregnancy. She underwent two repeat uterine evacuation procedures, an ultrasonic examination and a diagnostic laparoscopy before the unruptured tubal pregnancy was diagnosed. Both pregnancies probably occurred during the same menstrual cycle.

Adult↗
PubMed1979

Cholesterol solubility in organic solvents.

The 37 degree cholesterol solubilities in over 50 solvents, including the homologous n-alkanols through dodecanol and homologous ethyl carboxylates through the undecanoate, and the 37 degree beta-sitosterol solubilities in the n-alkanols through decanol are reported. Additionally, solubility data for cholesterol at 7, 17, and 27 degrees in the alcohol series were obtained. These measurements allowed the calculation of heats of solution for cholesterol in the alkanols, which range from 7.5 kcal for methanol to 4.3 kcal for decanol and which tend to decrease, although irregularly, with increasing alkanol chain length. A solubility maximum in all of these series for both solutes was observed between a chain length of six and seven. A surprisingly irregular, odd-even alternating solubility pattern was noted for cholesterol in the alkanols at all four temperatures. Experimental evidence indicated that this pattern was due to solvent-induced crystalline changes, presumably solvate formation, in each alkanol solvent through C10. Overall, the solubility studies screened solvents for their utility in dissolving cholesterol and, thus, cholesterol gallstones. To these ends, some limited dissolution experiments were performed, which indicated that the solution rate is directly related to the measured solubility in organic solvents. The dissolution behavior is thus different from micellar bile salt solutions, in which a significant interfacial barrier controls kinetics.

Cholesterol↗
PubMedDate not supplied

Progression of left main coronary artery stenosis following left anterior descending coronary artery angioplasty.

Although recent clinical experience indicates a high success rate, percutaneous transluminal coronary angioplasty (PTCA) is still associated with serious complications which usually occur during or shortly after the procedure and are principally related to the lesion or segment of vessel being dilated. We report 2 cases of subacute progression within months of left main stenosis following successful, uncomplicated left anterior descending (LAD) coronary PTCA. Identification of left main trunk involvement may mandate earlier follow-up or intervention.

Adult↗
PubMedDate not supplied

Outpatient laparoscopy with local anesthesia.

Since March 1974, laparoscopic sterilizations have been performed on patients under local anesthesia at The Hope Clinic for Women, an outpatient facility that is not based in a hospital. No major surgical complications have resulted from these procedures, and less than 1% of the patients experienced minor complications. Neither general anesthesia nor hospitalization has been necessary for any of the women sterilized. The results of this study show that outpatient laparoscopy, when performed by a highly skilled surgical team, is a safe procedure that does not present additional risks to the patient.

Adult↗