RESUMEN
Sgms1 encodes sphingomyelin synthase 1, an enzyme in the sphingosine-1-phosphate signalling pathway, and was previously reported to underlie hearing impairment in the mouse. A new mouse allele, Sgms1tm1a, unexpectedly showed normal Auditory Brainstem Response thresholds. We found that the Sgms1tm1a mutation led to incomplete knockdown of transcript to 20 % of normal values, which was enough to support normal hearing. The Sgms1tm1b allele was generated by knocking out exon 7, leading to a complete lack of detectable transcript in the inner ear. Sgms1tm1b homozygotes showed largely normal auditory brainstem response thresholds at first, followed by progressive loss of sensitivity until they showed severe impairment at 6 months old. The endocochlear potential was consistently reduced in Sgms1tm1b mutants at 3, 4 and 8 weeks old, to around 80 mV compared with around 120 mV in control littermates. The stria vascularis showed a characteristic irregularity of marginal cell surfaces and patchy loss of Kcnq1 expression at their apical membrane, and expression analysis of the lateral wall suggested that marginal cells were the most likely initial site of dysfunction in the mutants. Finally, significant association of auditory thresholds with DNA markers within and close to the human SGMS1 gene were found in the 1958 Birth Cohort, suggesting that SGMS1 variants may play a role in the range of hearing abilities in the human population.
RESUMEN
OBJECTIVE: Patients with severe mental illness (SMI) face health inequalities that lead to under treatment of diseases such as cancer and result in increased mortality. There is literature addressing this issue for SMI patients in high-income countries but few for those in low- and middle-income countries. This review aims to draw attention to the health inequalities and the compounding factors faced by SMI patients in low- and middle-income countries. The relevance of integration of psycho-oncology in the care of SMI patients with cancer is integral to reduce disparities and address varied contributory factors. METHODS: The literature review was conducted by searching through two databases which includes PubMed and Google Scholar. We searched for articles using keyword search terms: severe mental illness, SMI, schizophrenia, bipolar disorder, cancer, low- middle-income countries, low- and middle-income countries, psycho-oncology, HPV vaccine, cancer incidence, cancer mortality, cancer control, cancer screening, cancer treatment and palliative care. RESULTS: A total of 80 research articles were included in our literature review. We found that there was an increased requirement for adapting to the changing disease landscape in low- and middle-income countries. An improvement on aspects such as vaccination, screening and prevention is necessary, and also efforts to change social stance towards SMI is crucial. CONCLUSION: There is an increase incidence of cancer in low- and middle-income countries, and the number of patients with SMI in low- and middle-income countries is also rising. This is due to social, psychological, economical and healthcare factors. Low- and middle-income countries must consider improving these aspects in order to adapt to the changing landscape.
