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Biomedical subjects

D R Kent

Publications and source records attributed to D R Kent.

35 records · Page 2Linked to original sources
PubMed1977

Unilateral tuboovarian autoamputation.

Six cases of unilateral tuboovarian absence are reviewed. In four, the peritoneal cavity contained a separate ovoid structure. In two of these, the pathologist could identify the remnant as a phagocytized ovary. In a third patient, the ovoid body was seen fixed to the contralateral ovary during laparoscopy. Subsequently, it was identified radiologically as a calcific density. In the fourth case, an intact ovary was separated from the uterus and engulfed by omentum. If a total embryogenic error or selective dysgenesis of the urogenital fold occurs, ipsilateral anomalies usually involve adjacent structures of both the urinary and genital systems. Howerver, no anomalies of the uterus and urinary structures appeared evident in any reviewed case. Therefore, adnexal torsion with subsequent infarction necrosis and autoamputation represents the most likely explanation for this phenomenon.

Adult↗
PubMed1976

Abnormal cervical cytology in the teen-ager: a continuing problem.

Abnormal cervical cytology is being discovered in an alarming number of sexually active teen-agers. Over an 18 month period, cytology consistent with mild dysplasia or worse was noted in 188 of 2,655 teen-agers screened. This represents a rate of 70.8 per thousand. Colposcopically directed biopsies in 65 patients revealed 15 cases of severe dysplasia-carcinoma in situ. Cryosurgery was the principle method of treatment and, combined with colposcopy, is a safe and effective means of managing these patients.

Adolescent↗
PubMed1976

The making of a colposcopist. A safe and sensible approach.

A program was established to determine the accuracy of colposcopy at our institution. Forty-three patients with cytologic or histologic evidence of severe dysplasia or worse underwent diagnostic conization following satisfactory colposcopy. Thirty patients subsequently had either therapeutic conization or hysterectomy preceded by biopsy only. In all 73 cases, the surgical specimen did not reveal a more advanced lesion. However, when the colposcopy was unsatisfactory, the rate of error was 20.8%. It is our opinion that colposcopy is a safe and valuable technique as long as one recognizes the need for training and understands the indications for further diagnostic studies. The use of the colposcope for the evaluation of abnormal cervical cytology has increased steadily over the last few years, and several excellent courses are now offered throughout the United States. Armed with a certificate from such a course, many gynecologists then become self-proclaimed colposcopists in spite of warnings to the contrary by the instructors. In addition, supervision by experienced personnel is not always available. How, then, does one indeed become an accomplished colposcopist to the point that he or she can safely spare the patient the risk, inconvenience and expense of diagnostic cervical conization? Although several recent publications 2,5,6,9,11 document the diagnostic accuracy of colposcopically directly biopsies, we feel each individual should develop and evaluate his or her own skill before altering or abandoning conventional methods of diagnosis and management. The purpose of this report is to present our experience with colposcopy utilizing a program which can perhaps serve as a model to other clinicians.

Biopsy↗
PubMed1976

Experience with the use of the Carboflator for establishing pneumoperitoneum.

Safe and adequate pneumoperitoneum is dependent upon intraperitoneal pressure and not upon the number of liters of gas insufflated. Volume of gas delivered depends upon the size of the patient and whether there is any possible leakage. The Carboflator is a useful instrument for establishing controlled insufflation of gas and fail-safe intraperitoneal pressure.

Laparoscopes↗
PubMed1976

Association of liver tumors with oral contraceptives.

Benign hepatocellular neoplasia occurring in 22 women receiving oral contraceptive steroids but no other known hepatotoxins is reported for the first time from a registry for liver tumors associated with oral contraceptives. A review of recent literature has yielded 45 cases including 3 previously reported by the authors. This striking increase in what were formerly rare primary liver tumors in young women strongly suggests a cause and effect of relationship. Eighteen patients presented with intrahepatic or extrahepatic rupture and hemoperitoneum with hemorrhagic shock due to vascular changes within their liver tumors. Five died as a direct or indirect result of preoperative or postoperative blood loss. The predominant lesions were focal nodular hyperplasia, hepatic adenoma, and hamartoma. Multiple synonymous nomenclature used to describe the histopathology of these tumors is disquieting and requires clarification. For diagnosis, enzyme determinations are not helpful. However, radionucleide liver scans, sonography, and celiac arteriography may be of value. Clinical surveillance must be the primary means for identification of this potentially lethal adverse phenomenon among 50,000,000 oral contraceptive users.

Adult↗
PubMed1976

Prostaglandin E2 induction of labor for fetal demise.

Intrauterine fetal demise is a source of anxiety to both patient and physician. Heretofore, the standard treatment was either careful observation until the patient went into labor or attempt at induction of labor with oxytocin. Unfortunately, oxytocin stimulation has not proven to be uniformly successful for this problem. Prostaglandin E2 suppositories have been shown to be effective in inducing uterine evacuation after intrauterine fetal demise. In the opinion of the authors, this approach will in the future replace the sometimes dangerous and emotionally laden convention of watchful delayed therapy.

Adolescent↗
PubMed1975

Liver tumors and oral contraceptives.

Benign hepatocellular neoplasia has been found in 23 patients receiving oral contraceptives of various types. Because primary liver tumors are rare, this marked increase in incidence within 5 years suggests a cause-and-effect relationship. Since progestogens are enzyme inducers it is possible that they accelerate oncogenesis by increasing toxic metabolites which cannot be excreted due to the cholestatic effect of estrogens. Vascular changes and the hypercoagulation state of pill users may act synergistically to produce hemorrhagic necrosis and tumor rupture. Liver scans, celiac arteriography, and standard liver function tests are impractical and ineffective in the identification of the patient at risk. Management of the suspect patient with an intact liver should consist of biopsy at laparotomy so that the entire liver can be inspected. Observation, discontinuance of oral contraceptives, avoidance of similar steroids, and pregnancy should provide adequate prophylaxis against liver rupture. However, if a large blood-filled sinus lake or an area of coagulation necrosis is encountered, resection is imperative to prevent later rupture.

Adult↗
PubMedDate not supplied

Conformational analysis of the dipeptide taste ligand L-aspartyl-D-2-aminobutyric acid-(S)-alpha-ethylbenzylamide and its analogues by NMR spectroscopy, computer simulations and X-ray diffraction studies.

A dipeptide taste ligand L-aspartyl-D-2-aminobutyric acid-(S)-alpha-ethylbenzylamide was found to be about 2000 times more potent than sucrose. To investigate the molecular basis of its potent sweet taste, we carried out conformational analysis of this molecular and several related analogues by NMR spectroscopy, computer simulations and X-ray crystallographic studies. The results of the studies support our earlier model that an L-shape molecular array is essential for eliciting sweet taste. In addition, we have identified an aromatic group located between the stem and the base of the L-shape, which is responsible for enhancement of sweetness potency. In this study, we also assessed the optimal size of the essential hydrophobic group (X) and the effects of the chirality of the second residue toward taste.

Aminobutyrates↗
PubMedDate not supplied

Sweet and bitter taste: structure and conformations of two aspartame dipeptide analogues.

The synthesis and X-ray diffraction analysis of two dipeptide taste ligands have been carried out as part of our study of the molecular basis of taste. The compounds L-aspartyl-D-alpha-methylphenylalanine methyl ester [L-Asp-D-(alpha Me)Phe-OMe] and L-aspartyl-D-alanyl-2,2,5, 5-tetramethylcyclopentanyl ester [L-Asp-D-Ala-OTMCP] elicit bitter and sweet taste, respectively. The C-terminal residues of the two analogues adopt distinctly different conformations in the solid state. The aspartyl moiety assumes the same conformation found in other dipeptide taste ligands with the side-chain carboxylate and the amino groups forming a zwitterionic ring with a conformation defined by psi, chi 1 = 157.7 degrees, -61.5 degrees for L-Asp-D-Ala-OTMCP and 151.0 degrees, -68.8 degrees for L-Asp-D-(alpha Me)Phe-OMe. In the second residue, a left-handed helical conformation is observed for the (alpha Me)Phe residue of L-Asp-D-(alpha Me)Phe-OMe with phi 2 = 49.0 degrees and psi 2 = 47.9 degrees, while the Ala residue of L-Asp-D-Ala-OTMCP adopts a semi-extended conformation characterized by dihedral angles phi 2 = 62.8 degrees and psi 2 = -139.9 degrees. The solid-state structure of the bitter L-Asp-D-(alpha Me)Phe-OMe is extended: while the crystal structure of the sweet L-Asp-D-OTMCP roughly adopts the typical L-shaped structure shown by other sweeteners. The data of L-Asp-D-(alpha Me)Phe-OMe are compared with those of its diastereoisomer L-Asp-L-(alpha Me)Phe-OMe. Conformational analysis of the two taste ligands in solution by NMR and computer simulations agrees well with our model for sweet and bitter tastes.

Aspartame↗
PubMedDate not supplied

Role of oral contraceptive agents in the pathogenesis of liver tumors.

Since the introduction of oral contraceptive steroids in 1960 there has been a sharp increase in the incidence of benign liver tumors. Epidemiologic and other evidence links focal nodular hyperplasia and hepatic cell adenoma to the use of these agents. The risk increases with long-term exposure. The majority of patients were less than 35 years old. Most patients were exposed to mestranol (ME) alone or alternately with ethinylestradiol, both synthetic steroidal estrogens. Inability to demethylate ME in the smooth endoplasmic reticulum of hepatocytes may allow massive accumulation of oncogenic metabolites. This is probably a pharmacogenetic variable in a small number of women. Cholestasis, hypervascularity, induction of intracellular enzyme systems, thrombogenesis, and thickening of arterial and venous walls are other known effects of synthetic estrogens and progestogens. All may contribute to the pathogenesis of liver tumors. Many patients are asymptomatic until there is rapid expansion of the tumor. Pain occurs when Glisson's capsule stretches. Intrahepatic bleeding and liver rupture are common sequelae. Ligation of the hepatic artery may be lifesaving in the face of exsanguinating liver bleeding. Reports of regression with observation alone are encouraging. Instances of progression of unresected adenomas to rupture during subsequent pregnancy dictate avoidance of sex steroids in patients with hepatic neoplasia. Sonography, computerized axial tomography, radionuclide scans, and selective celiohepatic angiography are useful methods for the diagnosis of liver tumor in the symptomatic patient. There is a primary need to develop biochemical methods for detecting patients at risk for developing liver tumors. Epidemiologic research and central reporting of case histories are needed in the search for common factors.

Adult↗