Parkinson disease: a new link between monoamine oxidase and mitochondrial electron flow

Two factors that contribute to the progression of Parkinson disease are a brain defect in mitochondrial respiration and the generation of hydrogen peroxide (H2O2) by monoamine oxidase (MAO). Here we show that the two are linked. Metabolism of the neurotransmitter dopamine, or other monoamines (benzylamine, tyramine), by intact rat brain mitochondria suppresses pyruvate- and succinate-dependent electron transport. MAO inhibitors prevent this action. Mitochondrial damage is also reversed during electron flow. A probable explanation is that MAO-generated H2O2 oxidizes glutathione to glutathione disulfide (GSSG), which undergoes thiol-disulfide interchange to form protein mixed disulfides, thereby interfering reversibly with thiol-dependent enzymatic function. In agreement with this premise, direct addition of GSSG to mitochondria resulted in similar reversible inhibition of electron transport. In addition, the monoamines induced an elevation in protein mixed disulfides within mitochondria. These observations imply that (i) heightened activity and metabolism of neurotransmitter by monoamine neurons may affect neuronal function, and (ii) apparent defects in mitochondrial respiration associated with Parkinson disease may reflect, in part, an established increase in dopamine turnover. The experimental results also target mitochondrial repair mechanisms for further investigation and may, in time, lead to newer forms of therapy.

Assessing Tumor Size by MRI and Pathology in Type I Endometrial Carcinoma to Predict Lymph Node Metastasis

Introduction

Lymphatic spread is the most common route of spread of endometrial carcinoma, and the most frequently involved lymph nodes are those of the external iliac group. MRI is one of the best imaging tools for the preoperative evaluation of patients with endometrial carcinoma. The objective of the current study is to analyze the relationship between tumor size and lymph node metastasis in patients with type I endometrial carcinoma.

Methods

This is a prospective observational study performed in the Department of Obstetrics and Gynaecology at Liaquat National Hospital, Karachi, Pakistan. The duration of the study was from January 2020 to January 2021. During this period, 86 patients with biopsy-proven type I endometrial carcinoma were selected. Tumor size was measured by MRI. All participants underwent a total abdominal hysterectomy, bilateral salpingo-oophorectomy, and bilateral pelvic lymphadenectomy. Histopathological evaluation was performed according to the College of American Pathologists (CAP) protocols, and staging was performed using the 2009 International Federation of Gynecology and Obstetrics (FIGO) staging system. Lymph nodes were considered positive or negative, irrespective of their number.

Result

Of the 86 patients, 25 (29.1%) had positive lymph node metastasis. The mean tumor size with positive lymph node metastasis by MRI and histopathology was 7.86 cm and 10.21 cm, respectively. Tumor size determined by MRI and histopathology was significantly associated with lymph node metastasis (p < 0.01 and p < 0.01, respectively). Tumor size was positively correlated with lymph node metastasis (r = 0.715). The cutoff value of >6.5 cm by MRI was established as the statistically significant differentiator of lymph node metastasis. The calculated sensitivity and specificity were 88% and 90.16%, respectively, with an area under the curve (AUC) of 0.920. The cutoff value of >8 cm by histopathology was established as the statistically significant differentiator of lymph node metastasis. The calculated sensitivity and specificity were 80% and 88.52%, respectively, with an AUC of 0.907.

Conclusion

Our results showed that lymph node metastasis in patients with type I endometrial carcinoma can be predicted by tumor size. This may help incorporate adequate surgical skills and management plans in the treatment course of type I endometrial carcinoma.

Diagnostic accuracy of procalcitonin in maternal plasma to detect early intra-amniotic infection in preterm premature rupture of the membranes with respect of highvaginal swab as gold standard

Objective:

To determine the diagnostic accuracy of procalcitonin in maternal plasma to detect early intra-amniotic infection in Preterm premature rupture of the membranes (PPROM) with respect of high vaginal swab as gold standard

Methods:

A cross-sectional study was conducted at Liaquat National Hospital, Karachi, from February to August 2017. The blood sample of women with PPROM were collected to measure procalcitonin level. PCT1 and PCT2 were run along with the sample for the accuracy of the results. Sensitivity, specificity, PPV, NPV, and diagnostic accuracy of procalcitonin were calculated taking HVS C/S as gold standard.

Results:

Out of total 150 women, mean age was 28.78±4.79 years. Mean gestational age was 30.79±3.07 weeks. Mean procalcitonin level was 0.13±0.24 ng/ml. Intra-amniotic infection was diagnosed in 48.7% cases through procalcitonin levels and 51.3% through HVS culture and sensitivity. Sensitivity, Specificity, PPV (Positive predictive value), NPV (Negative predictive value) and accuracy were 87%, 91.8%, 91.78%, 87%, and 89.3% respectively. For females with gestational age ≤32 weeks, sensitivity, specificity, and diagnostic accuracy were 83.9%, 90.4%, and 87.03% respectively. For females with gestational age >32 weeks, sensitivity, specificity, and diagnostic accuracy were 95.2%, 92.5%, and 95.23% respectively.

Conclusion:

Diagnostic accuracy of maternal blood procalcitonin levels were found satisfactory in detection of early intra-amniotic infection in PPROM.