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Biomedical subjects

K Jones

Publications and source records attributed to K Jones.

At least 361 records · Page 20Linked to original sources
PubMed1989

Pulmonary vasodilation with prostacyclin in primary and secondary pulmonary hypertension.

Twenty-three patients with pulmonary hypertension underwent right cardiac catheterization and measurement of their response to a short-term infusion of prostacyclin. Pulmonary vasodilation with a greater than 20 percent fall in PVR occurred in all five patients with primary pulmonary hypertension where the predominant lesions were plexogenic; in three out of five patients where the predominant lesions were thrombotic; in three out of five patients with pulmonary hypertension and obstruction of proximal vessels; in three out of five patients with COPD; in both patients with pulmonary fibrosis due to sarcoidosis; and in the one patient with pulmonary veno-occlusive disease, where the pulmonary vasodilation was offset by a fall in arterial oxygen content. Prostacyclin is a safe and effective drug to use for testing the response of the pulmonary circulation to a vasodilator in pulmonary hypertension due to different causes. Short-term testing for a vasodilator response, with a view to instituting long-term therapy, should not be restricted to those patients with primary pulmonary hypertension due to plexogenic pulmonary arteriopathy.

Adult↗
PubMed1989

Asthma--still a challenge for general practice.

Asthma is probably the commonest chronic disease in the United Kingdom, and its attendant morbidity extends outside the possible scope of the hospital sector. Innovations to improve the care of asthma must therefore come from general practice. The need for such care initiatives is demonstrated by the rising mortality and morbidity from this condition, and by the evidence of less than optimum treatment at both the primary and secondary care levels. This paper reviews this evidence, and considers possible solutions to the problems raised. Pragmatic guidelines are offered for the promotion of good asthma care, while the need for proper evaluative research is stressed.

Asthma↗
PubMed1989

Appendicectomy at cholecystectomy--an appraisal.

The effect of incidental appendicectomy in patients undergoing elective biliary surgery has been studied prospectively in 430 patients. In 236 patients the appendix was removed at the time of biliary surgery; in 194 patients the appendix was not removed or had already been removed at a previous operation. There was no significant difference between the two groups with regard to the incidence of septic complications--especially wound infection--more general complications, or in the mean post-operative stay in hospital. Histological examination of the macroscopically normal appendices revealed a surprising incidence of pathology (greater than 50 per cent). Provided the patient receives routine antibiotic prophylaxis, there appears to be a case for removing the appendix at the time of cholecystectomy if it is readily accessible.

Adolescent↗
PubMed1989

Vascular tumors of the head and neck: presentation, prognosis, and treatment dilemmas.

Vascular tumors of the head and neck are a heterogeneous group of neoplasms, ranging from such common, benign lesions as facial hemangiomas to rare malignant tumors such as angiosarcomas. Because many of these tumors are quite rare and may occur in areas unfamiliar to the non-otolaryngologist, such as the nasopharynx, larynx, and middle ear, their presentation and differential diagnosis may not be familiar to the general medical practitioner. In addition, the treatment of many of these lesions is still evolving, with the advent of preoperative embolization and laser excision improving the morbidity of what may still be a difficult surgical removal. The authors review the presentation, treatment, and prognosis of the more common vascular tumors of the head and neck.

Adult↗
PubMed1989

In vitro activity of dactimicin and other aminoglycosides against bacteria producing aminoglycoside-modifying enzymes.

Dactimicin is a new pseudo-disaccharide aminoglycoside, originally isolated from cultures of Dactylosporangium matsuzakienzae sp. nov., which is chemically related to astromicin. In this study the in vitro activity of dactimicin has been determined against strains of bacteria producing characterized aminoglycoside-modifying enzymes and has been compared with that of gentamicin, tobramycin, netilmicin and amikacin. Minimum inhibitory concentrations were determined using an agar incorporation technique in Mueller-Hinton agar with an inoculum of approximately 10(4) cfu. Dactimicin was resistant to inactivation by a number of different acetyltransferases (AAC), produced by species of the Enterobacteriaceae, most of which inactivated gentamicin, tobramycin and netilmicin. The exception was an AAC(3')-I produced by an isolate of Escherichia coli, which inactivated gentamicin and dactimicin but not tobramycin, netilmicin and amikacin. Dactimicin was inactivated by the adenyltransferases (AAD) AAD(2") and AAD(9), produced by Pseudomonas aeruginosa, but not by an AAD(4')(4"), produced by a strain of Staphylococcus aureus, nor by an AAD(2") produced by a strain of E. coli. Dactimicin was inactivated by a combination of a phosphotransferase (APH) APH(2") and an AAC(6') produced by strains of S. aureus. The results suggest that dactimicin may retain useful antibacterial activity against many gentamicin-resistant strains of bacteria belonging to the Enterobacteriaceae and some gentamicin-resistant strains of S. aureus.

Acetyltransferases↗
PubMed1988

Tetrahydroisoquinoline lacks dopaminergic nigrostriatal neurotoxicity in mice.

1,2,3,4-Tetrahydroisoquinoline (TIQ) has been reported to occur in human brain, with its content being 10-fold higher in the brain of a patient with Parkinson's disease (PD) than in that of a control subject. This congener of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) could be formed in brain by the condensation of phenylethylamine with metabolically formed formaldehyde. Phenylethylamine contents are greatly increased in the tissues of untreated patients with phenylketonuria. We injected C57 black mice repeatedly with maximal tolerated doses of TIQ, but later found no reduction in the contents of dopamine and its metabolites in their striata. We doubt that TIQ is a cause of PD, especially since the disorder has not been reported to occur in elderly patients with phenylketonuria.

Animals↗
PubMed1988

Genital neoplasms treated by en bloc resection and penile retroversion in horses: 10 cases (1977-1986).

The medical records of 10 horses with invasive neoplasms of the penis, prepuce, and/or superficial inguinal lymph nodes in which treatment involved en bloc resection and penile retroversion were reviewed. All were geldings and ranged in age from 12 to 25 years (mean, 19 years). Evaluation of biopsy specimens obtained before surgery confirmed lymphosarcoma in 1 horse and squamous cell carcinoma in 9 horses. Typical history included swelling, ulceration, and abscessation of the penis and prepuce and large superficial inguinal lymph nodes. Complications after surgery included dehiscence of the urethrostomy site (4 horses), dehiscence of the ventral skin incision (1 horse), urine scalding of 1 hind limb (1 horse), cystitis (1 horse), severe hemorrhage (1 horse), and diarrhea (1 horse). One horse was euthanatized during hospitalization, because of severe dehydration secondary to diarrhea. At necropsy, firm nodules were scattered in the pulmonary parenchyma, myocardium, thyroid gland, parathyroid glands, cranial mediastinum, kidneys, and hilar lymph nodes. Microscopic examination of the nodules revealed undifferentiated carcinoma. Nine horses were discharged from the hospital between 1 and 5 weeks after surgery. The mean follow-up interval was 27 months (range, 6 to 96 months). Eight horses had no evidence of recurrence. One horse had recurrence of neoplasm at 6 months and was euthanatized 12 months later.

Animals↗
PubMed1988

2-Phenylpyridine and 3-phenylpyridine, constituents of tea, are unlikely to cause idiopathic Parkinson's disease.

Idiopathic Parkinson's disease (PD) is likely to be caused by one or more unidentified neurotoxins, present in the environment or formed endogenously, which progressively damage dopaminergic nigrostriatal neurons. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is an experimental neurotoxin which produces biochemical and neuropathological changes in lower primates and mice and in humans inadvertently exposed to it that closely resemble those found in PD. 2-Phenylpyridine (2-PP) and 3-phenylpyridine (3-PP), both of them present in tea, are the only MPTP analogues that are known to be present in the human diet. We exposed C57 black mice, animals very sensitive to the dopaminergic neurotoxicity of MPTP, to prolonged parenteral and oral administration of large doses of 2-PP, and to prolonged parenteral administration of the N-methylated tetrahydro derivatives of 2-PP and 3-PP. The latter are closer chemical analogues of MPTP than are 2-PP and 3-PP themselves. None of these MPTP analogues lowered the contents of dopamine and its metabolites in the striatum of mice. We speculate that the neurotoxins which cause PD are unlikely to resemble MPTP structurally, and we suggest that the search for chemical causes of PD should be directed to a wider variety of compounds encountered by humans.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Evaluation of unplanned interruptions in radiotherapy treatment schedules.

One of the major radiobiological interests has been to maximize the effectiveness of the time-dose relationship in the clinical setting. Current explorations include altered fractionation schedules, multiple daily fractions and hypofractionation. Patient compliance to standard radiotherapy treatment schedules is taken for granted. To evaluate the true rate of compliance, the charts of all new patients treated from July 1, 1984 through June 30, 1985 were reviewed. The overall incidence of unplanned interruptions was 54% (361/668). The frequency of interruptions is significantly higher in patients treated to the primary site as compared to those treated for metastasis (59.8% and 35.6% respectively). The duration of the interruptions varied: 12.7% of the patients missed only 1 day, 25% missed 2 to 5 days, 38% had interruptions totalling 6-15 days, and in 24% the total exceeded 15 days. The most frequent cause of the unplanned interruptions was a rest resulting from unusually adverse tissue reactions (46.8%-169/361). Although this study has documented that unplanned interruptions are a major problem, the impact on local control and survival cannot be determined from our data. A retrospective review of multi-institutional studies such as those conducted by the Patterns of Care or RTOG might show that one of the major causes of failure is unplanned interruptions.

Humans↗
PubMed1988

Artificial insemination: a comparison of pregnancy rates with intrauterine versus cervical insemination and washed sperm versus serum swim-up sperm preparations.

A four-cycle artificial insemination protocol was undertaken, with luteinizing hormone (LH) timing, to compare washed sperm and serum swim-up sperm preparations and cervical and intrauterine insemination. Of the 75 patients entered into the protocol series, 63 finished all 4 cycles. During the treatment period, 24 patients became pregnant, 20 of whom were donor (AID) pregnancies (out of 52 patients) and 4 were husband (AIH) pregnancies (out of 11 patients). Seventy-five percent of the pregnancies were intrauterine, whereas only 25% were from cervical inseminations. Sixty-two percent of the pregnancies were due to serum swim-up sperm preparations, and 38% were due to washed sperm preparations. The data indicate substantially higher pregnancy rates can be obtained with intrauterine insemination and suggest that additional studies are necessary to determine if the method of sperm preparation significantly influences pregnancy rates.

Cervix Uteri↗
PubMed1988

Achondrogenesis type I: delineation of further heterogeneity and identification of two distinct subgroups.

Achondrogenesis has traditionally been divided into type I (Parenti-Fraccaro) and type II (Langer-Saldino). We studied the clinical, radiologic, and morphologic features of 17 cases previously diagnosed as achondrogenesis type I to define whether there is even further heterogeneity. On radiographic analysis, two distinct groups of patients were defined based on the presence or absence of rib fractures and ossification of the vertebral pedicles, ischium, and fibula. Two distinct chondroosseous morphologic patterns were observed that directly correlated with the radiographic grouping. One group had round vacuolated chondrocytes with inclusion bodies; the other had collagenous rings around the chondrocytes. We conclude that achondrogenesis type I (Parenti-Fraccaro) consists of two distinct disorders: type IA, which corresponds to the cases originally published by Houston et al. and Harris et al., and type IB, which corresponds to the case originally published by Fraccaro. Analysis of Parenti's case suggests the diagnosis of achondrogenesis type II. All three types of achondrogenesis appear to be inherited as autosomal recessive traits.

Enchondromatosis↗
PubMed1988

What happens to patients after upper and lower gastrointestinal tract barium studies?

We investigated the occurrence of new constipation, diarrhea, nausea, vomiting, visible blood in stool, abdominal pain, black stools, belching, and flatus in 324 outpatients following upper or lower gastrointestinal tract barium procedures. We also evaluated the roles of age, sex, patient mobility, and types of barium enema (single- or double-contrast). At least one new symptom was reported after 51% of all examinations. Constipation was the most frequently reported single symptom after barium meal or small bowel examinations. Fifty percent of all constipation occurred following upper gastrointestinal examinations. Abdominal pain was common in patients of the seventh decade, especially following barium enema. Nausea typically followed barium swallow or upper gastrointestinal series. Belching and passage of flatus were the most frequently reported symptoms after barium enema, both single- and double-contrast. No significant relationship between the frequency of symptoms and patient age, sex, or the type of barium enema was established.

Adult↗
PubMed1988

Large angle p

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Journal Article↗
PubMed1988

Using the (p

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Journal Article↗